so, over the easter weekend I completed my small mini monitors with the CHR70.
they are 4 liter sealed, using a high pass capacitor (680uF) to both extend the low end and to flatten the low response (normally in 4 liters sealed there would be a hump). I have applied a notch filter (47uF, 0.39mH, 2.7ohm) as bsc.
the cabinets are made from black MDF and have 3 coats of clear varnish only. I liked the look of this black MDF so much, that I decided to name them "Black Beauty" (I just read this book to my joungest as bed time reading)
they are 4 liter sealed, using a high pass capacitor (680uF) to both extend the low end and to flatten the low response (normally in 4 liters sealed there would be a hump). I have applied a notch filter (47uF, 0.39mH, 2.7ohm) as bsc.
the cabinets are made from black MDF and have 3 coats of clear varnish only. I liked the look of this black MDF so much, that I decided to name them "Black Beauty" (I just read this book to my joungest as bed time reading)
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the sound is realy good, stil plenty of low, and the high (after some experimenting with the toe in) is very nice, not as sharp as with other metal cones is this price bracket. not as nice as the Alpairs, but they are near double the price so was not expecting that either.
I made some quick *) measurements using Arta of the final result, not bad at all I'd say
*) this was the first project that I used Arta, so in time it was not that quick, I spent most of the day setting up the program, fiddling the (also new) soundcard, and testing the combination, but once that was done, the measurement went prety quick
I made some quick *) measurements using Arta of the final result, not bad at all I'd say
*) this was the first project that I used Arta, so in time it was not that quick, I spent most of the day setting up the program, fiddling the (also new) soundcard, and testing the combination, but once that was done, the measurement went prety quick
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planet10 said:
lol, I actually don't have the option to be lazy. These are for a friend as a wedding gift so I can't leave them unfinished. They aren't as top heavy as I thought they would be. On carpet they kinda are but on a hard floor they might be ok without a base. Eliminating the top void/ballast would help too IMO.
I finished the Lotus BVR's this morning after I went and got some screws that would fit the drivers' mounting holes. After some quick wiring they were finished.
The first word or sound that comes to mind is WOW
These things are just unreal! I've only listened to them for about 10 minutes but I'm blown away. First, before I ramble on about these things I should let you know what I have to compare them to. My usual setup for a long time was a set of HSU research book shelf speakers with a pair of peerless XXLS 12's. Now I've been getting used to the frugal horns that I built last month with some of dave's modified FE126 drivers.
I'm using the Lotus BVR plan that Scott and Dave created and I'm running a pair of drivers in each cabinet. I've got the driver in the front baffle a half basket up and the driver on the side a half basket down. The driver on the side of the cabinet is about 3.5" at it's center from the front baffle face.
First thing I noticed from the moment I lit them up was the bass response. Ignoring the fact that it's even there in the first place, the second surprise is that it's beautiful....no other word to describe it. Much better low end than the frugals that I have. I don't think I have the frugals set up very well in terms of room placement (don't have a choice) and that hurts them I think. But since the vents on the lotus design fire forward, at the listener, it seems to work great even in a poorly set up room. The drivers don't move very much for the amount of low end they are providing.
I have the drivers on the sides pointed towards the center of the sound stage at the moment. I plan to play with their direction by swapping the cabinets left to right and seeing how they differ. At the moment I'm kinda running out of space in my room though so it will have to wait till I move some stuff.
PS: Dave, that rasp you told me to buy a while back came in handy during the build. Thank you.
PPS: Scott, the front baffle is 5" wide on the interior piece of wood. The driver's flange is 4.88" wide. What is left at the edges is a paper thin piece of wood. It's so close it's ridiculous.
The first word or sound that comes to mind is WOW
These things are just unreal! I've only listened to them for about 10 minutes but I'm blown away. First, before I ramble on about these things I should let you know what I have to compare them to. My usual setup for a long time was a set of HSU research book shelf speakers with a pair of peerless XXLS 12's. Now I've been getting used to the frugal horns that I built last month with some of dave's modified FE126 drivers.
I'm using the Lotus BVR plan that Scott and Dave created and I'm running a pair of drivers in each cabinet. I've got the driver in the front baffle a half basket up and the driver on the side a half basket down. The driver on the side of the cabinet is about 3.5" at it's center from the front baffle face.
First thing I noticed from the moment I lit them up was the bass response. Ignoring the fact that it's even there in the first place, the second surprise is that it's beautiful....no other word to describe it. Much better low end than the frugals that I have. I don't think I have the frugals set up very well in terms of room placement (don't have a choice) and that hurts them I think. But since the vents on the lotus design fire forward, at the listener, it seems to work great even in a poorly set up room. The drivers don't move very much for the amount of low end they are providing.
I have the drivers on the sides pointed towards the center of the sound stage at the moment. I plan to play with their direction by swapping the cabinets left to right and seeing how they differ. At the moment I'm kinda running out of space in my room though so it will have to wait till I move some stuff.
PS: Dave, that rasp you told me to buy a while back came in handy during the build. Thank you.
PPS: Scott, the front baffle is 5" wide on the interior piece of wood. The driver's flange is 4.88" wide. What is left at the edges is a paper thin piece of wood. It's so close it's ridiculous.
italynstylion said:
Told ya ...
italynstylion said:
Again, told ya ...
Just wait until they break in. The minor irregularities you hear now will disappear.
Henkjan, those are nice. I've been toying with the idea building a small sealed enclosure because a friend wants some surrounds and they'd be great for that. I'm a little surprised at the amount of rise high end. I can't say that I hear that in mine.
re: 3 way floor stander
I was also thinking about doing a 2.5-way setup, just using all the same speaker. 3 CHR-70s, one running tweet, one running mid AND bass, and one running only bass
The difference is very subtle, really. You have two midwoofers with a filter on both cutting the midrange down from the baffle step, or you have one driver running full volume midrange, and a second one running (essentially) none. Of course, since I'm going to be doing all first order filters for the crossovers, all the transitions will be rather gradual. In the end it's probably just a matter of which one is less complex to build. Thoughts?
I'm thinking I'm just going to have to try both
I was also thinking about doing a 2.5-way setup, just using all the same speaker. 3 CHR-70s, one running tweet, one running mid AND bass, and one running only bass
The difference is very subtle, really. You have two midwoofers with a filter on both cutting the midrange down from the baffle step, or you have one driver running full volume midrange, and a second one running (essentially) none. Of course, since I'm going to be doing all first order filters for the crossovers, all the transitions will be rather gradual. In the end it's probably just a matter of which one is less complex to build. Thoughts?
I'm thinking I'm just going to have to try both
italynstylion said:
Glad they're working. There are advantages & disadvantages to front or rear firing horns -as a personal preference, I tend to go with forward firing (as if anyone couldn't work that out
), especially for this style cabinet, which is operating over a relatively narrow BW & you don't have concerns over midrange output interering with the direct radiation from the driver. Excursion from this box with a single driver is pretty acceptable -you wouldn't want to be cranking Motorhead at live SPLs in a barn conversion, but in a modest space listening levels, certainly decent, especially as the MA drivers have plenty of travel. By doubling up the number of drivers, you're instantly hacking driver excursion; each should be moving about 1/4 that of a single unit for a given SPL (it halves by adding a second unit, and then that is halved again by sharing it between the two drivers). More dynamic headroom & ultimate linear SPL capability is the result.
No it's not.
Yes, you have to be careful, but from what you say, you managed it, and are fairly pleased with the results?
Yes Scott. very pleased with the results. I haven't even lined the interior with anything yet so I'm interested to see what effect lining some of the walls will have.
These speakers sound very live if I can use that word. The first song I turned on for my girlfriend was Jason Miraz-I'm Yours. About 5 seconds into the song she said, "It sounds like he's in the room..."
And I said, "yep..that's the point!"
These speakers sound very live if I can use that word. The first song I turned on for my girlfriend was Jason Miraz-I'm Yours. About 5 seconds into the song she said, "It sounds like he's in the room..."
And I said, "yep..that's the point!"
I suspect the former -according to the published data (and the MA published specs are trustworthy, unlike most) there's a slow rise above the telephone band up to ~12KHz, the level of which is similar to the small designed in centered around 500Hz. 30 degrees off axis rolls that off nicely, & you're unlikely to need to be that far off.
Lining the interior will cut down on unwanted reflections & some higher harmonic modes in the chamber that will be interfering with the output. It will likely sound less attention-grabbing, but smoother & easier to listen to over an extended period. I design for minimal damping though, so go easy with it.
Lining the interior will cut down on unwanted reflections & some higher harmonic modes in the chamber that will be interfering with the output. It will likely sound less attention-grabbing, but smoother & easier to listen to over an extended period. I design for minimal damping though, so go easy with it.
OK, I more or less came to the same conclusion after looking at the datasheet
on the lining, What material do you suggest.. I usually use wool-felt for wall lining and acrylic fibre (the wool like stuff) for volume damping. I was planning on some felt behind the driver (50% of rear wall and top) and some BAF in the bottom part of the cab
on the lining, What material do you suggest.. I usually use wool-felt for wall lining and acrylic fibre (the wool like stuff) for volume damping. I was planning on some felt behind the driver (50% of rear wall and top) and some BAF in the bottom part of the cab
tresch said:
You should be XOing 300-500 Hz. Not a lot of point going 2.5 way. With the "bass" drivers in series they will have the same sensitivity as the single mid-tweeter (if you are using a voltage amp). Could be some issues with having to deal with baffle-step. Maybe 4 CHR-70 in series/parallel XOed to a single CHR-70 mid-tweet at just below the bafflestep.
dave
There are some things I haven't tested out myself and thus I am curious about, as I haven't found really concrete info on it, yet.
In regards to serial wiring, you have two speakers each receiving half the power from the amp. Each speaker is quieter, but you have twice the moving surface area. Does this equal out? As far as acoustic volume, which is louder, one speaker with 50 watts, or two, each receiving 25? I'm sure this is a complex question that varies depending on the efficiency of the speaker, and how the efficiency changes by volume.
If I were to have a 3 speaker configuration, with one speaker as a mid-tweet, and two bass drivers crossed over right at the baffle step, I would want the bass drivers to be MORE sensitive overall than the high, to accomodate for the baffle step. If two speakers in series are essentially the same sensitivity as the mid-tweet, I would still need to attenuate the mid-tweet in order to compensate for baffle step.
On the other hand, would it be reasonable to wire the bass drivers in parallel to increase output, and then attenuate the bass drivers to match the mid-tweet? This would result in an overall impedance between 6-8 ohms*, depending on how much resistance needs to be added to the bass network, which would be more friendly to your basic Home Theater amplifier, which is going to be driving these speakers.
*two 4ohm bass drivers in parallel = 2 ohms + some amount of arbitrary resistance, wired series with a 4ohm mid-tweet = 6 or more ohms
I'm just thinking out loud, feel free to ignore me or humor me with criticism! I really need to get a hold of the Loudspeaker Design Cookbook one of these days...
In regards to serial wiring, you have two speakers each receiving half the power from the amp. Each speaker is quieter, but you have twice the moving surface area. Does this equal out? As far as acoustic volume, which is louder, one speaker with 50 watts, or two, each receiving 25? I'm sure this is a complex question that varies depending on the efficiency of the speaker, and how the efficiency changes by volume.
If I were to have a 3 speaker configuration, with one speaker as a mid-tweet, and two bass drivers crossed over right at the baffle step, I would want the bass drivers to be MORE sensitive overall than the high, to accomodate for the baffle step. If two speakers in series are essentially the same sensitivity as the mid-tweet, I would still need to attenuate the mid-tweet in order to compensate for baffle step.
On the other hand, would it be reasonable to wire the bass drivers in parallel to increase output, and then attenuate the bass drivers to match the mid-tweet? This would result in an overall impedance between 6-8 ohms*, depending on how much resistance needs to be added to the bass network, which would be more friendly to your basic Home Theater amplifier, which is going to be driving these speakers.
*two 4ohm bass drivers in parallel = 2 ohms + some amount of arbitrary resistance, wired series with a 4ohm mid-tweet = 6 or more ohms
I'm just thinking out loud, feel free to ignore me or humor me with criticism! I really need to get a hold of the Loudspeaker Design Cookbook one of these days...
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